GaN Rectifying Device Low On-Resistance via Trap Density Control
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Solution Overview
Problem
Gallium nitride (GaN) rectifying devices face high on-resistance issues due to high carrier recombination rates, leading to increased heat generation and time degradation, despite their potential for high breakdown voltage, which limits their performance and efficiency.
Innovation Solution
Reducing carrier trap density in p-type and n-type gallium nitride semiconductor layers to prevent non-radiative recombination and promote radiative recombination, allowing energy to be released as light instead of heat, thereby reducing on-resistance and enhancing the Baliga's figure of merit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If GaN is used as semiconductor material for rectifying device, then breakdown voltage and heat resistance are improved, but on-resistance becomes excessively high
Solution Approach 1:
The patent applies parameter changes by precisely controlling the acceptor impurity concentration to less than 1×10^19 cm^-3 and donor impurity concentration to less than 1×10^18 cm^-3. This parameter optimization resolves the contradiction by achieving both high breakdown voltage (exceeding 1 kV) and low on-resistance (not more than 6.3 mΩcm²), overcoming the conventional limitation where high breakdown voltage materials exhibited excessively high on-resistance.
2Strength
If acceptor impurity concentration is increased to heighten breakdown voltage, then reverse voltage resistance is improved, but on-resistance increases significantly
Solution Approach 1:
The patent resolves this contradiction through precise parameter control, setting acceptor impurity concentration to less than 1×10^19 cm^-3. This optimized parameter range enables the device to achieve breakdown voltage exceeding 1 kV while maintaining on-resistance at not more than 6.3 mΩcm², thereby simultaneously improving reverse voltage resistance without excessively increasing on-resistance.
3Loss of energy
If microfabrication such as trench structure is applied, then on-resistance is reduced, but device complexity increases
Solution Approach 1:
The patent resolves this contradiction by optimizing material parameters (impurity concentrations) rather than applying complex microfabrication structures. By controlling acceptor impurity to less than 1×10^19 cm^-3 and donor impurity to less than 1×10^18 cm^-3, the invention achieves low on-resistance (not more than 6.3 mΩcm²) through material composition optimization, thereby reducing device complexity compared to trench structure approaches.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach effectively lowers on-resistance and improves the Baliga's figure of merit, enhancing the performance of GaN rectifying devices by reducing time degradation and heat generation, while maintaining high breakdown voltage.
Implementation Method 1
Reducing carrier trap density in p-type and n-type gallium nitride semiconductor layers to prevent non-radiative recombination and promote radiative recombination, allowing energy to be released as light instead of heat
Data Source
AI summary
A gallium nitride rectifying device includes a p-type gallium nitride based semiconductor layer and an n-type gallium nitride based semiconductor layer, the two layers forming a pn junction with each other. The p-type gallium nitride based semiconductor layer has a carrier trap (level) density of not more than 1×1018 cm−3, or the n-type gallium nitride based semiconductor layer has a carrier trap (level) density of not more than 1×1016 cm−3.